Avoid possible regression test instability in timestamp.sql.

tglsfdc · tglsfdc · commit 47169c25500a · 2019-04-15T16:20:01.000-04:00
Concurrent autovacuum could result in a change in the order of the live rows in timestamp_tbl. While this would not happen with the default autovacuum parameters, it's fairly easy to hit if autovacuum_vacuum_threshold is made small enough to allow autovac to decide to process this table. That's a stumbling block for trying to exercise autovacuum aggressively using the core regression tests. To fix, replace an unqualified DELETE with a TRUNCATE. There's a similar DELETE just above (and no order-sensitive queries between), so this doesn't lose any test coverage and might indeed be argued to improve it. Discussion: https://postgr.es/m/17428.1555348950@sss.pgh.pa.us
diff --git a/src/test/regress/expected/timestamp.out b/src/test/regress/expected/timestamp.out
@@ -74,7 +74,7 @@ SELECT count(*) AS two FROM TIMESTAMP_TBL WHERE d1 = timestamp(2) without time z
 (1 row)
 
 COMMIT;
-DELETE FROM TIMESTAMP_TBL;
+TRUNCATE TIMESTAMP_TBL;
 -- Special values
 INSERT INTO TIMESTAMP_TBL VALUES ('-infinity');
 INSERT INTO TIMESTAMP_TBL VALUES ('infinity');
diff --git a/src/test/regress/sql/timestamp.sql b/src/test/regress/sql/timestamp.sql
@@ -44,7 +44,7 @@ SELECT pg_sleep(0.1);
 SELECT count(*) AS two FROM TIMESTAMP_TBL WHERE d1 = timestamp(2) without time zone 'now';
 COMMIT;
 
-DELETE FROM TIMESTAMP_TBL;
+TRUNCATE TIMESTAMP_TBL;
 
 -- Special values
 INSERT INTO TIMESTAMP_TBL VALUES ('-infinity');
